[JBA87]

I am coming from an Audi S6, where there is (to my knowledge) no "piggy back tuning."

Can someone explain to me the operative and implicative differences of a "piggy back" vs. "ECU" tune. I don't full comprehend the difference.

Also I'm shopping around and here are the tunes I am aware of (please add to the list) and feel free to comment on the differences:

Piggyback
JB4
Racechip
Dinan

Tune
Evolve
Vivid racing
Noelle
HCP
Dme
Eurocharged


Any others ?